Shield for amplifier or detector tubes



Dec. 8, 1925.

E. H. LERCHEN SHIELD FOR AMPLIFIER OR DETECTOR TUBES Filed Oct. 10, 1922 Fi l INVENTOR. Edward/ Awaken M A TTORNEYS Patented Dec. 8, 1925.

EDWARD H. LERCHEN, OF EAST GRANGE, NEW JERSEY.

SHIELD FOR AMPLIFIER R DETECTOR TUBES.

Application filed October 10, 1322. Serial No. 598,515.

To all whom it may concern:

Be it known that I, EDWARD ll. Lnucrrnn, a citizen of the United States, residing at .East Orange, in the county of Essex and State of New Jersey, have invented new and useful Improvements in Shields :t'or Amplifier or Detector Tubes, 01? which the following is a specification. This invention relates to a radio detector or amplifier tube in which a non-magnetic cage covers the said tube in order to protect it from the effects of stray electromagnetic currents.

An object of the invention is to provide the cage with a ground connection to conduct and carry off into the earth any stray electrical energy or impulses which are thrown into the air by various causes such as electric generators or lightning discharge.

Another object of the invention is to prevent the radio frequency oscillations of the grid and its conductors from escaping and causing same to affect other tubes in proximity to amplifying tubes within the same circuit.

It is well known that unnecessary noises in radio pliotron vacuum conductor and amplifying tubes other than those for which the instrument is in resonance with the sending station are caused by high frequency currents conducted by the air and it is the main object of the present invention to prevent the stray currents from disturbing the receiving instrument.

The invention resides in the novel combination hereinafter described and claimed, reference being made tothe accompanying drawing in which:

Fig. 1 represents a vertical section of an instrument embodying this invention.

Fig. 2 is a side elevation of the same.

In the drawing the numeral 5. designates a socket having a series of binding posts 6 which are connected to the grid 7 plate 8,

positive and negative filament 9. The grid,

' the top and sides of the tube so as to shield plate, positive and negative filament are mounted on a base or stem 10 inserted into the socket member and a bayonet joint 11 looks the two to ether. The negative binding post of the ament is also connected to the ground, as indicated in Fig. 1. On the base 10 is fixed a vacuum tube or bulb 12 of glass suitable for covering and sealing the grld and its associates as is well known.

On the upper end of the base is arranged a collar 13 having an upwardly turned rim 14; and the collar is fastened or attached to the said base by means of a pin 15 extending through the collar into the side of the base, or other suitable means. The cage 16 is made of fine woven mesh of non-magnetic metal such as copper and is supported on the collar and a bayonet joint 1? loclrs the cage to the collar. The cage is connected to the negative post by means of a wire 18 attached to the side of the cage. The cage can be readily removed simply by turning it and moving it upward to free the pin from the slot. The collar is preferably made of copper and it is in direct contact with the metal sheeting of the base, thus covering the lower end of the cage and. making a complete non-magneticshield around the tube. By means of this cage the stray radio and audio electromagnetic energy and impulses known as high frequency currents which are not in resonance with the instrument and which would otherwise pass through the walls of the tube are intercepted and conducted to the ground and thereby carried 0E.

As shown in the drawing the cage is inverted thus covering the top and the sides of from the slot and lifted up over the bulb.

I claim:

1. A shield for electron discharge tubes the tube. from stray electromagnetic currents, means for removabl locking the cage to the collar, and means or conducting t e currents from the cage to the negative connection. I

2. A shield for electron discharge tubes comprising a base provided With a socket having positive and negative conductors, an electron detector or amplifier tube mounted in the socket, a collar having a bayonet slotted rim secured to the upper portion of the base, an inverted open bottomed cage supported on the collar to cover the top and sides of the tube so as to shield the tube from stray electromagnetic currents, said cage having a pin to engage the slot for 16 removably locking the cage to the collar, and means for conducting the currents from the cage to the negative connection thence to the ground. 7

In testimony whereof I have hereunto set 15 my hand.

EDWARD H. LERGHEN. 

